【摘要】 采用多物质欧拉与拉格朗日耦合算法,对框架结构和混凝土地面采用Lagrange单元、空气和炸药采用多物质ALE单元,建立流固耦合有限元模型,对一个五层的钢框架结构在近地爆炸作用下冲击压力波的传播过程、结构冲击响应和变形以及破坏过程进行了数值模拟。数值模拟分析结果表明,拉格朗日-欧拉耦合算法较好地模拟了爆炸冲击波在介质中的传播和作用在结构上的爆炸荷载效应。在爆炸近区,空气爆炸冲击波的衰减速率快;爆炸产生强烈的冲击波首先使钢框架结构正面的柱和梁柱节点区产生很大的塑性变形,钢框架柱在发生爆炸的瞬间失去承载能力,最终导致建筑物整体倒塌。考虑结构变形和流体荷载间的相互影响可以较真实地模拟结构在爆炸荷载作用下的连续倒塌过程,为研究结构在爆炸荷载作用下的连续倒塌提供了有效手段。更多还原

【Abstract】 Using the multi-material Eulerian and Lagrangian coupling algorithm,a fluid-structure coupling of finite element model was construced,which consisted of Lagrange element for simulating steel frame structure and concrete ground,and multiple ALE element for simulating air and TNT explosives material.Numerical simulations of the shock pressure wave propagation,structural shock responses and deformation,and failure procedure of a five-storey steel frame structure in the event of an explosion near above ground were performed.The numerical analysis results show that the Lagrangian and Eulerian coupling algorithm provides a good simulation of the shock wave propagation in the media and explosion loading effects on the structure.The amplitudes of blast pressure waves near to explosion sources attenuate significantly.The columns and joints of steel beam to column in the front steel frame structure generate enormous plastic deformation subjected to intense blast shock wave,and the columns lose carrying capacity,subsequently lead to the collapse of the whole structure.The approach that considers the coupling influence between the structural deformation and the fluid load well simulates the progressive collapse process of structures,and provides an effective tool for studying the progressive collapse mechanism of structures under blast load.更多还原